Well, let's stand back for a moment and think about this strange idea called PS4K

1. Both Sony and Microsoft made the same mistake when they started with the PS4/XOne: In order to be able to cry "First!", both used half-baked 28nm chip libraries to unveil their 1080p systems. It has turned out neither system is really able to do it (without major sacrifices). Had they waited for matured libraries, either system could have come out one year later with about 20% higher performance (staying around the same thermal envelope required for consoles), actually hitting the 1080p target...

2. Now Sony makes the same mistake again (or even a worse one). If we assume the leaked specs are true - 30+% CPU power, 220%+% , (unknown TMU/ROP counts) GPU power, ONLY 24% more ram bandwidth -, we can conclude that they must use early 14/16nm chip libraries (to stay within the thermal envelope). We haven't even heard of the state of  making 14/16nm CPUs (outside of Intel which has had a really hard time it seems), and the first 14/16nm gpus were probably designed with something similar to "hot needle design rules" by AMD/NVidia, again to be able to cry "First!". So this new PS4K SoC is likely a "we barely made-it" 14716nm chip design.

3. If MS were clever, they would wait another year for matured 14/16nm libraries. And then come with their 14/16nm version (with more ram) which would absolutely trounce the PS4K.

4. Why would you even think about designing a PS4K (and pissing off 40M+ owners of a PS4)? Yes I understand the PS4 will prove to be too weak for driving "good looking VR" on the PSVR, but again, you will just piss off many of the  40M+ PS4 users when they try the PSVR this fall. Was it so difficult to move the required hardware into the PSVR unit (you already have an ASIC in there anyways)?

Basically yes and no.

If things pan out how I suspect they will, and we start having hardware reiterations every 3-4yrs that still maintains some level of support for all the previous hardware.... then that creates a new kinda console dynamic. 

There are those that will always be willing to cough out money for the cutting edge hardware. Be it that that hardware is $399/$499. They will be willing to do that every 3-4yrs. 

There are those that will not and will want you get it when it's comes down in price to $200/$300. 

The thing though is that when an upgrade is a certainty at a fixed price point, it makes the waiti g game useless. Cause if you choose to wait, you will wait forever cause there will always be something better coming out. 

So what happens will become something like this. we end up with 3 types of people. 

A: buy the next best thing every 3-4yrs and trade in/sell the last one they bought  for around $200. so technically they are spending only $200 on every new hardware jump. The value of the outgoing hardware holds cause it's still fully capable of playing the games. 

B: is more conservative and doesn't care about selling consoles. Buys every other hardware iteration, so every 6 years. 

C: is cheap and will only buy when hardware can be gotten for $200 or less. Is most likely going to be buying off those just about to upgrade. 

For Sony (and this is where I think they are going with this) 12 years from now we can very well be on PS4ver.D, but to them... it's the same as having an install base of 200M PS4s cause games made are sold to all 200M console holders. I've called this out before. months before any of this PS4k stories started. 

For one, all new PS4 games from October onward will be REQUIRED to have PS4.5 version which has 1080p+ resolution requirement.
They will also be required to have the SAME or HIGHER frames-per-second as PS4.0 version...  So higher fps seems likely to be common.
Other than that, I expect expanded scope/usage of stuff like GPU-physics, GPU-audio-raytracing, better lighting and graphic FX.
Morpheus/PSVR games already are pushed to have high frame-rates, for which they will have to sacrifice normal graphic niceties,
so the PS4.5 version of those VR games will be able to add back graphic FX, and/or go for even higher FPS, etc...

In Eurogamer's take on the leak, they discuss how there will be feature-parity across 4.0/4.5, i.e. that gameplay is supposed to be the same...
But then describe it by saying that PS4.0 might allow for 2-way split-screen gameplay, but PS4.5 might allow for 4-way split screen gameplay.
...Which really is a significant difference in gameplay IMHO, but that sort of thing may be technically allowable, apparently.

So he contrasts the PS4.5 situation, where there is one new fully documented spec that scales up the same platform...
To an undocumented variability stemming from several drive providers, which may have stealth regressed an existing spec.
Obviously his rant on "clarity" to devs re: what they are working with is just wholly inapplicable to the PS4.5 scenario.
From Oct onward, they will be REQUIRED to release games with specific performance requirements (1080p+) for PS4.5 spec.

Where do you get required from?

Sony really wants Neo support on all games from October onwards. While older titles can have Neo features patched in, the platform holder will not allow new titles to add Neo features at a later date.

They don't allow you to add it later from October onwards, but devs can still ignore it. The fps requirement is so that ps4.5k versions don't run worse due to using too high a resolution, which must be minimum 1080p. So higher fps is not likely to be common, it's simply required to be equal or more stable than ps4.

It all points mostly to a resolution bump for the Neo version, with likely downsampling to 1080p or upscaling to 4K. I doubt any devs will go for specific graphics or audio features for the NEO version, bump up shadow detail and reflections at most. No point in supporting a whole different enhanced lighting system.

Sinply look at the differences in XBox One and ps4 games, for ps4 and NEO it makes even less sense to add extra features. Resolution will be the biggest difference, next to a more stable frame rate. The question is will ps4 games now slip to 900p sub 30fps and XBox One versions to 720p? Or will things stay the same with NEO rendering at 1440p with better AA. (I guess the latter)

Eurogamer.  Which you seemed to also acknowledge in your follow up: (italicized/bolded)

I don't see why a variable-FPS game would NOT be expected to have higher fps given more hardware.

Not sure how you get "can still ignore" from "required".  
Patching is option for older games, new games must be "pre-patched" from Day 1, 1080p+ requirement applies.

Sure, but if a game suppors enhanced lighting/ whatever FX while in singleplayer on 4.0 (or in PC version etc),
and 4.5 can support that alongside higher performance multiplayer mode, than why wouldn't it do so?  
Sure, most devs won't invest in completely new engine details, but if they exist in some form, then I expect them to implement them if possible.
We see stuff like GPU physics implemented as hardware-dependent subset on PC games, don't see why it wouldn't apply here...
Of course they already have to fulfill 1080p minimum with same/higher FPS req., so tweaking other graphic FX alongside that optimization is plausible.
Obviously it's forseeable that 1st party devs will push more than 3rd parties to show off the system capabilities...
Although given x-platform games CURRENTLY offer more engine features on PC, those should also tend to carry over to PS4.5...

Sony really wants Neo support on all games from October onwards. While older titles can have Neo features patched in, the platform holder will not allow new titles to add Neo features at a later date.

Show me required in that sentence.

By higher fps not likely to be common, I mean don't expect 30fps - 60fps difference. Most NEO games will run more stable, still with the same fps cap.

Sure, but if a game suppors enhanced lighting/ whatever FX while in singleplayer on 4.0 (or in PC version etc),
and 4.5 can support that alongside higher performance multiplayer mode, than why wouldn't it do so? 

True, also for splitscreen I imagine, no drop in visuals neccesary.  However I was talking about the single player portion of the game.
Which raises another question, if the NEO multiplayer version is full of enhanced smoke and particle effects, which the ps4 base version would not see, wouldn't that be an advantage? Or the other way around, NEO players being able to see ps4 players coming around a corner by enhanced shadows, lighting or reflections.

But full featured split-screen at 1440p, co-op online without any downgrades, that's all very possible indeed.

The last part is pure speculation from Eurogamer. There is no way Sony will allow difference in gameplay between the 2 consoles.

You gotta love how random rumors start to get treated as fact so quickly. Even the price.

Seems like a bad idea, especially from a financial perspective, always has. What's the motivation here, the end game? Possibly a preemptive move? That's probably the hardest part for me to believe and why I never have.